Optical coupling module for testing an element to be tested, test unit, method for operating an optical coupling module, method for producing an optical coupling module, and control unit

Abstract

The present invention relates to an optical coupling module (105) for testing an element (135) to be tested, the optical coupling module (105) comprising a module carrier (107) having a test-signal portion (110) for emitting an optical test signal (125) to a coupling region (130) of the element (135) to be tested or for receiving an optical test signal (125) from the coupling region (130) of the element (135) to be tested, and a camera system (140) fixed to the module carrier (107) for identifying the position of the coupling region (130) of the element (135) to be tested in relation to the module carrier (105).

Description

[0001] Optical coupling module for testing an element under test, test unit, method for operating an optical coupling module, method for manufacturing an optical coupling module and control unit

[0002] The approach presented here provides an optical coupling module for testing an element under test, a test unit, a method for operating an optical coupling module, a method for manufacturing an optical coupling module, and a control unit according to the main claims. Such a module and method are known by design from US 2011 / 0279812 A1 and WO 2019 / 029765 A1.

[0003] From W02021 / 078318 Al, a wafer-level test method is known for testing optoelectronic chips arranged on a wafer with electrical interfaces in the form of contact pads and fixed optical interfaces in the form of optical deflection elements. In three adjustment steps, the wafer with one of the chips is aligned with a contacting module such that the electrical interfaces of the chip and the contacting module are in contact with each other and the optical interfaces of the chip and the contacting module (2) assume a maximum optical coupling position. The method is relatively complex.

[0004] US patent 2006 / 0109015 A1 discloses an optoelectronic probe module for testing chips (device under test - DUT) with electrical and optical inputs and outputs. If, as described in US patent 2006 / 0109015 A1, the coupling efficiency of the optical signal is optimized by collimating or focusing the optical beam, the entire probe module must be adjusted with high precision in the sub-pm range, which is very complex.

[0005] US Patent 2011 / 0279812 discloses a contact module for testing chips with electrical and optical inputs and outputs. The chip is mounted on a movable carrier, which allows for rough alignment with the contact module. This rough alignment is sensor-controlled, based on position monitoring of the chip or its alignment marks. This method is complex and prone to errors. US Patent 7412138 discloses optoelectronic alignment structures for wafer-level testing of optical and optoelectronic chips. This wafer-level test system uses optical and electronic probes to locate and align to an optoelectronic alignment structure and includes adjustment for maximum performance. The alignment procedure and structures are relatively complex.

[0006] To test photonically integrated circuits in high-volume manufacturing, for example, special units or test solutions, such as optoelectronic probe cards, are used. A key feature should be plug-and-play compatibility with existing wafer-level test equipment and wafer probers used in the high-volume production of conventional ICs. To achieve this, the insufficient positioning accuracies of conventional wafer probers (currently ±1.5 pm) for reproducible optical coupling should be compensated for by a suitable, position-tolerance-insensitive optical coupling principle. The required positioning accuracy is in the lpm or even sub-pm range. The exact value depends heavily on the coupling structure used on the PIC (grid) and the illumination / detection optics.Currently, UFO Probe technology can only measure PICs (photonic integrated couplers) where light is coupled to a surface via grating couplers (GCs). However, using the current technology with evanescent couplers is problematic.

[0007] Because active alignment requires optimizing the position of a fiber array (or individual fibers), such adaptation is relatively slow and therefore unsuitable for high-volume testing. Furthermore, a large amount of space is required for the tracking system, making this approach less suitable for use in a fully automated test environment (ATE). Another disadvantage of a typical test unit setup is that interference makes coupling both in and out very inefficient. Typical losses are in the range of several dB.

[0008] Against this background, an optical coupling module for testing an element under test is proposed, wherein the optical coupling module has the following features: a module carrier with a test signal section for outputting an optical test signal to a coupling area of ​​the element under test or for receiving an optical test signal from the coupling area of ​​the element under test; and a camera system fixed to the module carrier for capturing the position of the coupling area of ​​the element under test in relation to the module carrier.

[0009] A module carrier can be understood, for example, as a monolithic assembly in which light beams can be guided as test signals. For this purpose, the module carrier can, for example, have one or more waveguides or be transparent. A test signal section can be understood as the area of ​​the module carrier through which an optical test signal is coupled out of the module carrier and, for example, sent to a coupling area of ​​the element under test in order to couple into the element under test, or through which an optical test signal can be coupled into the module carrier for subsequent evaluation in a corresponding evaluation unit. A camera system can be understood, in this context, as an assembly with at least one image sensor that is designed and oriented to specifically capture the position of the coupling area of ​​the element under test.In this case, the camera system is fixed to the module carrier or embedded on or in the module carrier.

[0010] The approach presented here is based on the understanding that highly accurate positioning of the optical coupling module can be achieved by evaluating a signal from the camera system, which is fixed to the module carrier. This allows for precise positioning with minimal installation space requirements. For example, if the position of the optical coupling module is misaligned, the position of the module carrier relative to the element under test can be quickly and easily adjusted. Fixing the camera system directly to the module carrier also prevents misalignments of the optical coupling module relative to the element under test caused by tolerances or wear of the system. Such misalignments could, for example, result in insufficient power of the optical test signal being directed into or onto the coupling area.

[0011] A particularly advantageous embodiment of the approach proposed here comprises at least one image sensor and one imaging optical element, especially wherein the image sensor and the imaging optical element are arranged on different and / or opposite sides of the module carrier. Such an embodiment offers the advantage of enabling very precise focusing of the coupling area on the image sensor by using the image sensor in combination with the imaging optical element. At the same time, such an embodiment can have a very small installation space requirement.

[0012] Specifically, according to one embodiment of the approach proposed here, the imaging optical element can be configured as a microlens array or as a diffractive imaging system, in particular comprising at least one Fresnel lens or a metastructure. Such an embodiment offers the advantage that the imaging optical element can be formed particularly easily on or in the module carrier, and such an imaging optical element very efficiently enables corresponding observation of the position of the coupling region of the element under test.

[0013] The camera system can be fixed to the module carrier particularly securely if, according to one embodiment, the camera system is monolithically connected to and / or with the module carrier.

[0014] Another conceivable embodiment of the approach proposed here is one in which the camera system further comprises an illumination unit for illuminating the coupling area of ​​the element under test, particularly in which the illumination unit is arranged on the same side as an image sensor of the camera system or adjacent to the image sensor of the camera system. Such an embodiment offers the advantage of being able to clearly and precisely detect the position of the coupling area of ​​the element under test, even independently of the output of an optical test signal. Specifically, the illumination unit can, for example, be configured to output light with a different wavelength, shape, intensity, and / or duration than the optical test signal, so that indifference or interference with the light output by the illumination unit does not lead to a change in the optical test signal.

[0015] A particularly advantageous embodiment is proposed in which the camera system is designed to detect the distance of the coupling area of ​​the element under test from the module carrier. This also allows the positioning of the element under test in a z-direction, i.e., its height relative to the optical coupling module, to be detected. This enables, for example, the initial alignment of the element under test in an x- and / or y-direction, followed by an adjustment of the height or alignment of the element under test in a z-direction. In this way, electrical contact elements such as contact pins can be protected by avoiding the need for further alignment of the element under test in an x- and / or y-direction during the conversion process.

[0016] The position of the coupling area of ​​the element to be tested can be determined very clearly if, according to one embodiment, the camera system is arranged on a cantilever of the module carrier and / or if an optical path of the optical test signal and a viewing direction of the camera system intersect, or if the optical path of the optical test signal and the viewing direction of the camera system are skew to each other. For example, by arranging the camera system on a cantilever of the module carrier, it can be ensured that the camera system has the clearest possible view of the coupling area of ​​the element to be tested.In an arrangement of the camera system where the optical path of the optical test signal intersects with a viewing direction of the camera system, or where the optical path of the optical test signal and the viewing direction of the camera system are skewed towards each other, a very compact optical coupling module can be realized, in which the corresponding light path is guided through an interior of the module carrier, so that the module carrier as a whole has a very low installation space requirement.

[0017] A particularly advantageous embodiment of the approach proposed here is one in which the module carrier includes imaging optics for outputting the optical test signal to or into the coupling area of ​​the element under test, especially wherein the imaging optics comprise a curved mirror or a light deflection element for changing the beam direction of the optical test signal before it strikes the coupling area of ​​the element under test. Such an embodiment offers the advantage of allowing for a high degree of flexibility in the design of the external shape and / or the installation space requirements of the module carrier through the configuration of the imaging optics.

[0018] According to a further embodiment, a test unit for optically testing a test element is presented, wherein the test unit has the following features: a variant of an optical coupling module presented here; and an evaluation unit configured to send an optical test signal through the optical coupling module to the test element and to evaluate a test signal or evaluation signal received from the test element.

[0019] Even with such an embodiment, the aforementioned advantages can be implemented in a technically simple, cost-effective and efficient manner.

[0020] One embodiment of the proposed approach, which is particularly precise, incorporates a motion unit to move the element under test in response to a signal from the camera system. Such an embodiment offers the advantage, for example, of correctly positioning the element before testing, thus enabling optimal conversion or illumination of the optical test signal onto appropriately designed areas of the element.A particularly robust embodiment of the approach proposed here comprises at least one electrical contacting unit for contacting at least one electrical contact area of ​​the element under test, in particular wherein the contacting unit is configured to make electrical contact with the element under test after movement of the element under test in response to a signal from the camera system. Such an embodiment offers the advantage of being able to reliably test further functions of the element under test; in particular, it largely avoids mechanical damage to the contacting unit.

[0021] The aforementioned advantages can also be realized in a further embodiment of the approach proposed here as a method for operating a variant of an optical coupling module presented here, wherein the method comprises the following steps:

[0022] Evaluating the position of the element to be tested in relation to the module carrier using the camera system, and

[0023] Output of the optical test signal to or into the coupling area of ​​the element to be tested.

[0024] Alternatively, a method for manufacturing an optical coupling module according to a variant presented here can be implemented according to another embodiment, wherein the method comprises the following steps:

[0025] Provision of the module carrier; and

[0026] Training or attaching the camera system to or within the module carrier to create the optical coupling module.

[0027] These methods can be implemented, for example, in software or hardware, or in a hybrid form of software and hardware, for example in a control unit.

[0028] The approach presented here further creates a control unit designed to execute, control, and implement the steps of a variant of the method presented here in appropriate devices. This embodiment of the invention, in the form of a control unit, also allows the underlying problem to be solved quickly and efficiently.

[0029] For this purpose, the control unit can have at least one processing unit for processing signals or data, at least one storage unit for storing signals or data, at least one interface to a sensor or actuator for reading sensor signals from the sensor or for outputting data or control signals to the actuator, and / or at least one communication interface for reading or outputting data embedded in a communication protocol. The processing unit can be, for example, a signal processor, a microcontroller, or the like, and the storage unit can be flash memory or a magnetic storage device.The communication interface can be configured to read or output data wirelessly and / or via wired connections, whereby a communication interface that can read or output wired data can, for example, read this data electrically or optically from or output it into a corresponding data transmission line.

[0030] In this context, a control unit can be understood as an electrical device that processes sensor signals and outputs control and / or data signals accordingly. The control unit can have an interface, which may be implemented in hardware and / or software. In the case of a hardware-based interface, the interfaces can, for example, be part of a so-called system ASIC, which incorporates various functions of the control unit. However, it is also possible that the interfaces are separate integrated circuits or at least partially comprised of discrete components. In the case of a software-based interface, the interfaces can be software modules, which, for example, are located on a microcontroller alongside other software modules.

[0031] Also advantageous is a computer program product or computer program with program code that can be stored on a machine-readable carrier or storage medium such as a semiconductor memory, a hard disk memory or an optical memory and is used to carry out, implement and / or control the steps of the method according to one of the embodiments described above, in particular if the program product or program is executed on a computer, a control unit or generally a device.

[0032] Examples of the approach presented here are shown in the drawings and explained in more detail in the following description. It shows:

[0033] Fig. 1 shows a schematic representation of an embodiment of a test unit with an embodiment of an optical coupling module; Fig. 2 shows a schematic representation of another embodiment of a test unit with a different embodiment of an optical coupling module;

[0034] Fig. 3 shows a flowchart of an embodiment of a method for operating a variant of an optical coupling module presented here;

[0035] Fig. 4 shows a flowchart of an embodiment of a method for manufacturing a variant of an optical coupling module presented here;

[0036] Fig. 5 shows a block diagram of a control unit for executing a variant of the method for operating a variant of an optical coupling module presented here; and

[0037] Figure 6 shows a block diagram of a control unit for executing the method for manufacturing a variant of an optical coupling module presented here.

[0038] In the following description of favorable embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and acting similarly, without repeating these elements.

[0039] Figure 1 shows a schematic representation of an embodiment of a test unit 100 with an embodiment of an optical coupling module 105. The optical coupling module 105 comprises an imaging optic 110 on a module carrier 107, which is configured to transmit an optical test signal 115, for example, from an evaluation unit 120 via a waveguide 125 in the module carrier 105 to a coupling area 130 of an element 135 under test (DuT = device under test). This optical test signal 115 can be used, for example, to test the functionality of the element 135 under test, which is, for example, an optical component.The coupling area 130 can, for example, be designed as a grid coupler, such that very precise positioning of the optical coupling module 105 is required for coupling the optical test signal 115 into the coupling area 130, as otherwise the optical test signal 115 cannot be efficiently coupled into the coupling area 130. To ensure such precise positioning, the optical coupling module 105 has a camera system 140, which is arranged on a boom 145 of the optical coupling module 105. This boom 145 is designed as a projection above the imaging optics 110 and includes an imaging optical element 150 on a lower surface facing the coupling area 130 and an image sensor 155, which can also be referred to as a camera chip, on the upper surface opposite the imaging optical element 150.Furthermore, a lighting unit 160 is arranged next to or adjacent to the image sensor 155, which is designed to shine illumination light through the (preferably transparent) arm 155 onto the coupling area 130. The imaging optical element 150 and the image sensor 155 thus enable the position of the coupling area 130 in a corresponding beam path 165 to be detected, and this detected position is then, for example, also supplied to the evaluation unit 120 in a corresponding signal 170. In the evaluation unit 120, a movement unit 175 can then be controlled, for example, according to the signal 170, to move the element 135 to be tested, which is, for example, designed as an optical integrated circuit on a wafer, in corresponding directions 177, so that precise illumination of the optical test signal 125 into the coupling area 130 is possible.At the same time, it can also be ensured that the position of the element 135 to be tested is at a corresponding depth below the optical coupling module 105. This prevents, for example, contact units 180, which are designed, for instance, as contact needles of a probe 182, from already being in contact with corresponding contact areas 185 during repositioning. Such contact could otherwise cause these contact units 180 to be bent or otherwise damaged by a corresponding movement of the element 135 to be tested. Once the element 135 to be tested is correctly adjusted, the distance between the optical coupling module 105 and the element 135 to be tested can be reduced, so that the contact units 180 are electrically contacted with the corresponding contact areas 185.In this case, for example, the optical test signal 135 can be output to the coupling area 130, and a corresponding test signal 187 can then be read in via the coupling area 130, which can then be evaluated in the evaluation unit 120. This allows, for example, the correct functionality of the element 135 under test to be verified.

[0040] Figure 2 shows a schematic representation of another embodiment of a test unit 100 with a different embodiment of an optical coupling module 105. In contrast to the embodiment shown in Figure 1, the camera system 140 is now not arranged on a boom, but directly on the module carrier 105, so that the beam paths of the optical test signal 125 and the beam path 165 cross or are arranged at an angle to each other. However, such an embodiment offers the advantage of a very compact component for the optical coupling module 105, since the module carrier 107 does not need to include a boom 145.

[0041] In the approach presented here, the prober technology is thus supplemented by an additional imaging system, such as the camera system 140, which can capture and quickly compensate for the position of the gratings or the coupling area 130 relative to the optical coupling module 105. This eliminates the need for a complex optimization procedure (similar to that described in active alignment). At the same time, no bulky setup is required, as the camera system 140 can be directly integrated into the optical coupling module 105 of the UFO Probe Card (OLGA) or the test unit 100. Then, via a feedback loop, it can readjust either the DuT or the element 135 under test (via the prober) or the optical coupling module 105 itself for each DuT 135 in a single step. This method allows the use of illumination patterns adapted to the grating modes as test signals 125 when testing the element 135 under test, thus eliminating the need for overexposure (or...).(this is reduced to a minimum). This allows the efficiency of the UFO probe technology to be increased by orders of magnitude. Because the imaging system (camera system 140) and the coupling module 105 are advantageously monolithically connected (camera system 140 is, for example, integrated into coupling module 105), very precise positioning can be achieved. Since the positional tolerances of the grating couplers as coupling area 130 on a DuT 135 are typically very small, imaging only one (and optimizing for one) grating coupler(s) is a particularly suitable implementation.

[0042] Adjusting the probe is particularly suitable for fine-tuning, as this simplifies the setup of the probe card with the optical coupling module 105. Furthermore, no high-voltage supply is required for a piezoelectric element, which could interfere with the electronic measurement process. Alternatively, the optical chip itself can also be fine-tuned, for example, via a piezoelectric element.

[0043] Ideally, adjustments should be made in the free-flying probe mode (i.e., before contacting, for example, the contact units 180) to prevent damage to the needles required for electronic contacting. For this purpose, the image plane of the imaging optical element 165 should ideally lie in the area of ​​the lowered wafer on or in which the element 135 to be tested is located. The specific imaging system or camera system 140 should, for example, consist of a micro-optic or imaging optical element 150 and a miniaturized camera chip 155. A relatively small chip is required for the camera 155, the external dimensions of which should not exceed those of the optical coupling module 105. However, a relatively low resolution (240 x 320 pixels or less) is sufficient. The imaging of the DuT plane or the coupling area 130 onto the camera chip 155 can be achieved, for example, by…This is achieved via a micro-optical imaging system 150. Either a microlens array or a diffractive imaging system (Fresnel lens or metastructure) can be used as the imaging optical element 150. The latter can be applied directly to the OLGA or the module carrier 107 using various methods (lithographically or via laser-selective etching). Finally, an illumination unit 160 can be provided near the camera system 140. For this purpose, an LED or OLED can be used, for example. The light from the illumination unit 160 can be imaged onto the grating or coupling area 130 via the same optics or the same imaging optical element 150, which also serves for image acquisition by the image sensor 155. A particularly suitable design of the illumination unit 160 is an LED that emits in visible light, because this prevents unwanted coupling into the DuT or...The element 135 to be tested can be avoided, and a cost-effective silicon-based camera chip 155 can be used. The captured image can be evaluated using a suitable chip or evaluation unit 120 and appropriate software. Modern AI-based image recognition methods can be used for this purpose.

[0044] With reference to Figures 1 and 2 described above, two possible embodiments for implementing the camera system 140 on or in the module carrier 107 are presented. Both embodiments are approximately equivalent. In the embodiment according to Figure 1, the camera system 140 is placed directly above the grating coupler or coupling area 130. For this purpose, the optical chip or image sensor 155 is supplemented by a cantilever 145 on its front face on the module carrier 107. This simplifies the design of the imaging optical element 150. The disadvantage of this embodiment is the larger installation space required and the resulting greater minimum distance between the grating coupler or coupling area 130 and the contact areas 185 or the bond pads on the DuT or the element 135 to be tested. The second embodiment according to the illustration in Figure 2 increases the space requirement of the optical chip or image sensor 155.The optical coupling module 105 is not affected (or only minimally) because the imaging optical element 150 and the camera or image sensor 155 are integrated into or mounted on the existing optical coupling module 105. The disadvantage of this design is, on the one hand, the demanding design of the imaging optical element (it should accommodate a very high field of view), and on the other hand, this design prevents the two-dimensional distribution of the optical coupling points across the coupling module 105. Furthermore, imaging here is achieved through an area in the OLGA or the beam path 115 in which waveguides, for example, for guiding the optical test signal 125, may be located. However, since these structures are relatively small, image distortion caused by these waveguides is unlikely.

[0045] For the sake of clarity, the illumination beam path 165 and the cable routing of the camera system 140 and the LED or illumination unit 160 are not shown in Figures 1 and 2. However, a particularly suitable embodiment is to route the cables along the fiber direction of the optical coupling module 105.

[0046] The depth of field of the imaging system or camera system 140 should be designed such that the positional tolerances of the probe chuck in the Z-direction do not affect the imaging, but that the height of the wafer can simultaneously be determined in order to minimize the error in determining the position of the grating coupler or coupling area 130. This also has the advantage that the proposed system can also be used for precise adjustment of the height of the DuTs 135 relative to the probe card or module carrier 107 or the optical coupling module 105, thus simplifying the contacting of the electrical pads or contact areas 185.

[0047] The approach presented here is particularly advantageous due to the integration of a second imaging system 140, enabling an active feedback loop and allowing the positional tolerance to be compensated directly, i.e., without a slow optimization algorithm. In particular, the DuT or the element 135 under test does not need to be contacted or read out for optimization of the coupled light. Simultaneously, the grating illumination system or the output of the optical test signal 125 can be adjusted so that the illumination mode matches the mode of the grating coupler 130 well, thus enabling efficient coupling in and out. A further advantage of the invention is that the height of the DuT relative to the probe card or the optical coupling module 105 can be measured by the imaging system or camera system 140, allowing the typical overdrive of the probe or the coupling module 105 to be set more precisely than conventionally.

[0048] Figure 3 shows a flowchart of an embodiment of a method 300 for operating a variant of an optical coupling module presented here, wherein the method 300 comprises a step 310 of evaluating a position of the element to be tested in relation to the module carrier using the camera system and a step 320 of outputting the optical test signal to or into the coupling area of ​​the element to be tested.

[0049] Figure 4 shows a flowchart of an embodiment of a method 400 for manufacturing a variant of an optical coupling module presented here, wherein the method 400 comprises a step 410 of providing the module carrier and a step 420 of forming or attaching the camera system to or in the module carrier in order to manufacture the optical coupling module.

[0050] Figure 5 shows a block diagram of a control unit 500 for carrying out a variant of the method 300 for operating a variant of an optical coupling module presented here, wherein the control unit 500 comprises a unit 510 for evaluating a position of the element to be tested in relation to the module carrier using the camera system and a unit 520 for outputting the optical test signal to or into the coupling area of ​​the element to be tested.

[0051] Figure 6 shows a block diagram of a control unit 600 for carrying out the method 400 for manufacturing a variant of an optical coupling module presented here, wherein the control unit 600 comprises a unit 610 for providing the module carrier and a unit 620 for forming or attaching the camera system to or in the module carrier in order to manufacture the optical coupling module.

Claims

Patent claims 1. Optical coupling module (105) for testing an element (135) to be tested, wherein the optical coupling module (105) has the following features: a module carrier (107) with a test signal section (110) for outputting an optical test signal (125) to a coupling area (130) of the element (135) to be tested or for receiving an optical test signal (125) from the coupling area (130) of the element (135) to be tested; and a camera system (140) fixed to the module carrier (107) for detecting the position of the coupling area (130) of the element (135) to be tested in relation to the module carrier (105).

2. Optical coupling module (105) according to claim 1, wherein the camera system (140) has at least one image sensor (155) and one imaging optical element (150), in particular wherein the image sensor (155) and the imaging optical element (150) are arranged on different and / or opposite sides of the module carrier (105).

3. Optical coupling module (105) according to claim 2, wherein the imaging optical element (150) is configured as a microlens array or as a diffractive imaging system, in particular comprising at least one Fresnel lens or a metastructure.

4. Optical coupling module (105) according to one of the preceding claims, wherein the camera system (140) is monolithically connected to and / or with the module carrier (107).

5. Optical coupling module (105) according to one of the preceding claims, wherein the camera system (140) further comprises an illumination unit (160) for illuminating the coupling area (130) of the element (135) to be tested, in particular wherein the illumination unit (160) is arranged on the same side as an image sensor (155) of the camera system (140) or adjacent to the image sensor (155) of the camera system (140).

6. Optical coupling module (105) according to one of the preceding claims, wherein the camera system (140) is configured to detect the distance of the coupling area (130) of the element (135) to be tested from the module carrier (107).

7. Optical coupling module (105) according to one of the preceding claims, wherein the camera system (140) is arranged on a cantilever (145) of the module carrier (105) and / or wherein an optical path of the optical test signal (125) and a viewing direction of the camera system (140) intersect or wherein the optical path of the optical test signal (125) and the viewing direction of the camera system (140) are skew to each other.

8. Optical coupling module (105) according to one of the preceding claims, wherein the module carrier (107) has an imaging optic (110) for outputting the optical test signal (125) to the coupling area (130) of the element (135) to be tested, in particular wherein the imaging optic (110) has a curved mirror or a light deflection element for changing a beam direction of the optical test signal (125) before it hits the coupling area (130) of the element (135) to be tested.

9. Test unit (100) for optically testing a test element (135), wherein the test unit (100) has the following features: an optical coupling module (105) according to one of the preceding claims; and an evaluation unit (120) configured to send an optical test signal (125) through the optical coupling module (105) to the test element (135) and to evaluate a test signal or evaluation signal (187) received from the test element (135).

10. Test unit (100) according to claim 9, comprising a movement unit (175) to move the element (135) to be tested in response to a signal from the camera system (140).

11. Test unit (100) according to one of the preceding claims with at least one electrical contacting unit (185) for contacting at least one electrical contact area (185) of the element (135) to be tested, in particular wherein the contacting unit (180) is configured to make the electrical contact area (185) of the element (135) to be tested after a movement of the element (135) to be tested in response to a signal (170) of the camera system (140).

12. Method (300) for operating an optical coupling module (105) according to any one of claims 1 to 8, wherein the method (300) comprises the following steps: Evaluating (310) the position of the element to be tested (135) in relation to the module carrier (107) using the camera system (140), and Output (320) of the optical test signal (125) to or into the coupling area (130) of the element to be tested (135).

13. Method (400) for manufacturing an optical coupling module (105) according to any one of claims 1 to 8, wherein the method (400) comprises the following steps: Provision (410) of the module carrier (105); and Training (420) or attaching the camera system (140) to or in the module carrier (105) to produce the optical coupling module (105).

14. Control unit (500, 600) configured to execute and / or control the steps (310, 320; 410, 420) of one of the methods (300; 400) according to one of the preceding claims 11 to 12 or 13 in corresponding units (510, 520; 610, 620).

15. Computer program configured to execute and / or control the steps (310, 320; 410, 420) of one of the methods (300; 400) according to one of the preceding claims 11 to 12 or 13.

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